Applicant's disclosure is generally directed towards the location of a mobile device within a communications network. There are many traditional methods of locating a mobile device including, but not limited to, handset-based techniques and network-based techniques. These techniques may include, but are not limited to, Assisted-Global Positioning Satellite (A-GPS), Uplink Time Difference of Arrival (U-TDOA), Observed TDOA (O-TDOA), Enhanced Observed Time Difference (E-OTD), Electronic Cell Identification (E-CID), Radio Frequency (RF) fingerprinting, and Multiple Range Estimation Location (MREL) techniques, to name a few. Such techniques, however, may be ineffective in locating mobile devices in certain environments, e.g., urban environments, indoor environments, etc.
Several telecommunications industry reports have indicated a higher usage of mobile devices in such challenging environments as well as higher usage of location based applications in recent years. Mobile devices operating in these environments may be blocked from receiving GPS signals due to the signal attenuation of the satellite signals by building infrastructure and/or other environmental aspects. This same infrastructure may also attenuate the signals transmitted by cellular towers such that cellular service may be unavailable. RF repeaters or a Distributed Antenna System (DAS) may therefore be installed and/or implemented to amplify and distribute the appropriate signals to provide adequate coverage. Repeater/DAS systems, however, introduce signal delay and gain into the respective transmission path thereby resulting in a deleterious effect of decreasing the accuracy of a location system or even preventing a location from being computed or determined.
Therefore, there is a need in the art for a system and method to remove the dependence of location systems upon GPS and/or base station signals and may also remove the effect of signal delay and gain introduced by repeater and/or DAS coverage products upon location determination for a mobile device. There is also a need in the art to detect a mobile device of interest by monitoring the device's signal transmissions and determining the proximity of the mobile device to a sensor performing the monitoring function. This proximity detection function may be performed by an RF sensor, e.g., an independent RF sensor or an RF sensor embedded in an existing network component or apparatus.
In view of these needs, one embodiment of the present subject matter provides a method of determining the location of a mobile device in a communications network having one or more proximity sensors. The method may include receiving a request to locate the mobile device and tasking at least one of the proximity sensors to receive a signal transmission from the mobile device. One or more signal characteristics of the signal transmission from the mobile device may be measured by each tasked proximity sensor. A location of the mobile device may then be determined as a function of the measured characteristics by associating a fixed location with each tasked proximity sensor and determining the location of the mobile device as a function of one of the associated fixed locations.
Another embodiment of the present subject matter provides a method for determining a location of a mobile device in a communications network having a plurality of base station transceivers in communication with the mobile device. The method may include the steps of determining the location of the mobile device without utilizing signals received or transmitted to the base station transceivers by using proximity detection sensors deployed in the network and by determining the location of the mobile device as a function of information provided by ones of the proximity detection sensors.
A further embodiment of the present subject matter may provide a method of determining the location of a mobile device in a communications network having one or more proximity sensors. The method may include receiving a request to locate the mobile device and tasking at least one of the proximity sensors to receive a signal transmission from the mobile device. One or more signal characteristics of the signal transmission from the mobile device may be measured by each tasked proximity sensor. A location of the mobile device may then be determined as a function of the measured characteristic, wherein the measured characteristic includes range information.
An additional embodiment of the present subject matter may provide a method of determining if a mobile device is operating in a predetermined region of a communications network. The method may include receiving a request to locate the mobile device and tasking one or more proximity sensors in the network to receive a signal transmission from the mobile device. One or more signal characteristics of the signal transmission from the mobile device may be measured by the tasked proximity sensor. A fixed location may then be associated with each tasked proximity sensor and the proximity of the mobile device determined in the predetermined region using the associated fixed locations.
Yet another embodiment of the present subject matter provides a method for determining a location of a mobile device operating in a wireless communications network having an A-GPS positioning determining entity (PDE). The method may include receiving a location request for the mobile device and determining if the request is for a region in the network having a proximity detection system. If the region has a proximity detection system, then both the proximity detection system and the A-GPS PDE may be tasked to determine a location of the mobile device. If at least one of the proximity detection system and the A-GPS PDE provide a location result for the mobile device, then the uncertainty of the respective location result may be determined and a location result returned having the lowest uncertainty as the location for the mobile device. If neither the proximity detection system nor the A-GPS provide a location result for the mobile device, then a cell-identification may be utilized as the location for the mobile device. If the region does not have a proximity detection system, then the A-GPS PDE may be tasked to determine a location of the mobile device. If the A-GPS PDE provides a location result for the mobile device, then this location result may be utilized as the location for the mobile device. If the A-GPS does not provide a location result for the mobile device, then a cell-identification may be utilized as the location for the mobile device.
One embodiment of the present subject matter may provide a method for determining a location of a mobile device operating in a wireless communications network having an A-GPS PDE. The method may include receiving a location request for the mobile device and determining the location of the mobile device as a cell identification location if no location results are received from either the A-GPS PDE or a proximity detection system PDE. The location of the mobile device may be determined as a location result from the A-GPS PDE if the A-GPS PDE provides a location result having a lower uncertainty than a location result from the proximity detection system PDE. Further, the location of the mobile device may be determined as a location result from the proximity detection system PDE if the proximity detection system PDE provides a location result having a lower uncertainty than a location result from the A-GPS PDE.
A further embodiment of the present subject matter provides a method for determining a location of a mobile device operating in a wireless communications network. The method may comprise the steps of: receiving a location request for the mobile device and routing the request to a proximity detection system and a serving mobile location center (SMLC). The following steps may then be performed substantially in tandem: (i) tasking both the proximity detection system and the SMLC to determine a location of the mobile device, (ii) if at least one of the proximity detection system and the SMLC provide a location result for the mobile device, then determining the uncertainty of the respective location result and returning the location result having the lowest uncertainty as the location for the mobile device, and (iii) if neither the proximity detection system nor the SMLC provide a location result for the mobile device, then using a cell-identification as the location for the mobile device.
These and other embodiments of the present subject matter will be readily apparent to one skilled in the art to which the disclosure pertains from a perusal or the claims, the appended drawings, and the following detailed description.